---
title: Bundle with webpack
description: Learn about different webpack bundler configurations that can be customized.
---

import { Terminal } from '~/ui/components/Snippet';

> **warning** **Deprecated**: In SDK 50 and above, Expo Webpack has been deprecated in favor of [Expo Router](/router/introduction/). Learn how to [migrate from Expo Webpack to Expo Router](/router/migrate/from-expo-webpack/).

To enable Webpack web support, modify your [app config](/workflow/configuration) using the `expo.web.bundler` field:

```json app.json
{
  "expo": {
    "web": {
      "bundler": "webpack"
    }
  }
}
```

## Customizing the Webpack config

When you run `npx expo start --web` or `expo export:web` the CLI checks to see if your project has a **webpack.config.js** in the root directory. If the file doesn't exist in your project, then Expo uses the default `@expo/webpack-config` (preferred).

To edit the config, install `@expo/webpack-config` as a dev dependency and create a template **webpack.config.js** at the root of your project. This can be done by running the following command:

<Terminal cmd={['$ npx expo customize webpack.config.js']} />

You can now make changes to a config object based on the default config and return it for Expo CLI to use. Deleting the config will cause Expo to fall back to the default again.

If you create a new webpack config or make any changes to it you'll need to restart your webpack dev server by running:

<Terminal cmd={['$ npx expo start']} />

## Example

```js webpack.config.js
const createExpoWebpackConfigAsync = require('@expo/webpack-config');

// Expo CLI will await this method so you can optionally return a promise.
module.exports = async function (env, argv) {
  const config = await createExpoWebpackConfigAsync(env, argv);
  // If you want to add a new alias to the config.
  config.resolve.alias['moduleA'] = 'moduleB';

  // Maybe you want to turn off compression in dev mode.
  if (config.mode === 'development') {
    config.devServer.compress = false;
  }

  // Or prevent minimizing the bundle when you build.
  if (config.mode === 'production') {
    config.optimization.minimize = false;
  }

  // Finally return the new config for the CLI to use.
  return config;
};
```

## Editing static files

You can also use `npx expo customize` to generate static project files such as **index.html** and so on. These can be used to customize your project more familiarly.

All the files you select from the terminal prompt will be copied to a **web** directory in your project's root directory. Think of this directory as **public** in Create React App. The **web** is used instead of **public** because Expo webpack is web-only, the static directory does not work for Android or iOS apps. For mobile platforms, the platform-specific project files are included in **android** and **ios** directories.

Deleting any of these files will cause Expo webpack to fall back to their respective default copies.

### Why

- Customizing the favicon icon.
- Adding third-party API code to the `<head/>` in your **index.html**.
